A recent significant advancement in the field of generating low temperature refrigeration is the development of cryocoolers, such as the pulse tube system, wherein pulse energy is converted to refrigeration using an oscillating gas. Such systems can generate refrigeration to very low levels sufficient, for example, to liquefy helium. One important application of the refrigeration generated by such cryocooler systems is in magnetic resonance imaging systems. Other cryocooler systems are Gifford-McMahon cryocoolers and Stirling cryocoolers.
Conventional high frequency resonant linear motor driven cryocoolers employ an integrated cold head and driver unit. In this conventional arrangement the resonant linear motor is used as a mounting platform for the cold head or cryocooler resulting in a compact system with lower pressure-volume work losses.
One disadvantage of the conventional integrated system is that vibrations from the resonant linear motor, especially when the resonant linear motor is operating at a high frequency, may adversely affect the operation of the load to be cooled. This is particularly a problem when the cryocooler is employed to provide cooling to a magnetic resonance imaging system because the vibrations may interfere with the ability of the imaging system to provide effective clear imagery. Another disadvantage of the conventional integrated system is not having enough space on the magnet system to accommodate larger resonant linear motors.
Accordingly, it is an object of this invention to provide a resonant linear motor driven cryocooler system which can substantially avoid vibration transfer from the motor to the cryocooler while still enabling effective driving of the cryocooler by the motor.